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(No Model.)

2 Sheets-Sheet 1.

H. FRIEDEBORN. TWIN SCREW STEAM ENGINE.

No. 514,650. Patented Feb. 13, 1894.

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(No Model.) 2 Sheets-Sheet 2.

H. PRIEDBB-ORN. TWIN SCREW STEAM ENGINE.

UNITED STATES ATENT HERMANN FRIEDEBORN, OF MUNDEN, GERMANY.

TWIN-SCREW STEAM-ENGINE.

SPEGIFIGATIGN forming part of Letters Patent No. 514,650, dated February 13, 1894. Application filed August 18, 1893. Serial No. 483,463. (No model.)

To all whom it may concern.-

Be it known that I, HERMANN FRIEDEBORN, a subject of the King of Prussia, German Emperor, and a resident of Miinden, in the Provlnce of Hanover, Kingdom of Prussia, German Empire, have invented certain new and useful Improvements in Double-Cylinder Steam-Engines, of which the following is a specification.

My invention relates to double-cylinder steam-engines, as for instance twin-engines or compound-engines, in which two parallel shafts are turned by two cranks rotating in the same plane, and my improvements in such steam-engines relate: first, to the connection of said two cranks with each other and with a third, auxiliary or guide-crank, which also rotates in the same plane, and the angular positionof which constantly corresponds with the angular position of the other two cranks, and the purpose of which is to maintain the angular positions of said two main cranks at every movement in perfect accordance; secend, to the arrangement of the cylinder, or, in other words, to the mode of connecting the piston-rods with the three coupled cranks, before mentioned, in such a manner that the cylinders reciprocally overcome the dead points of their cranks; third, to the employment of said auxiliary or guide-crank as valvegear for both the cylinders, in order to simplify the construction of the engine generally, and the construction of the valve-motion es pecially.

In order to make myinvention more clear, I refer to the accompanying drawings, in which similar letters denote similar parts, and in which- Figure I is a frontview of the steam-engine; Fig. II a vertical section, taken on line 8--9 of Fig. I; Fig. III a detail, showing the reversing-lever; Fig. IV a back-view of the engine, the valve-motion being in section; Fig. V a part of the axle of the auxiliary crank, with parts of the valve-motion, drawn in a larger scale; Fig. VI avertical section, taken on line 10-11 of Fig. V, and Fig. VII isa detail of the valve-motion.

The two main-cranksa and a are connected with each other by the coupling-rod b, and with the auxiliary or guide-crank a by the two couplingrods b and b the rods b h and b forming a triangle. This coupled system a a a 1) b b is moved from the high-pressure cylindercand the low-pressure cylinder 0' by the connecting-rods cl and cl, which are crossing each other shortly below crank 0, The cylinders c and c are secured in an inclined position to the common frame 2, in which are also provided the bearings f and f for the crank axles g and g, the latter belonging to the auxiliary crank a Crank-axle g has a prismatic elongation 9 (Figs. II and V,) two opposite sides of which are provided with grooves g Into these latter are placed the slides h and h each of which has an oblique rib 7L both the slides are at their outer projecting ends connected by an intermediate part 2' (Fig. VII) of suitable shape.

The oblique ribs it hold the eccentric k, the latter having a long, quadrangular hole and suitable oblique "rooves within the broader sides of said hol, into which the ribs are catching. Eccentric 7c holds the two eccentric straps Z and Z, which act in known manner on the slide-valves or other kind of valves within the valve-chests m and m by the eccentric rods n and n.

A remarkable feature of my invention consists in the ring 0, Figs. II and V, which supports the elongation g within the hind part of the bearing f. Ring 0 rotates with crankaXle g or with its elongation g respectively, and has also suitable grooves for receiving the ribs 71. when the double-slide h h is axially moved; said grooves within ring 0 form, so to say, elongations of the grooves within eccentric 7c.

The purpose of the arrangement, described in the last three paragraphs, is to ettect the reversing of the valve-gear in a quick and re liable manner, without requiring a stoppage of the engine. This reversing is effected by displacing the double-slide 71 h axially within the grooves g of the prismatic elongation g of crank-axle g, so as to cause thereby a radial displacement of the eccentric 7a with its 1 straps Z Z, and, consequently, a corresponding movement of the valves.

The double slide it it rotates, as a matter of course, constantly 5 in order to move it axially during its rotation, the head of the double-slide with its connecting-part i is rounded at It Fig. V, and carries at that place a ring 13, Fig. 11, which is connected with the re verslng-lever q, Fig. III, the latter being piv-' 1 oted at z to any suitable part or projection of the frame.

Having thus fully described the nature of my invention, what I desire to secure by Letters Patent of the United States is- 1. In a double'cylinder steam-engine with two coupled main-cranks acting on two shafts, the combination with the main-cranks a a, of an auxiliary guide-crank 662 coupled to said cranks a a, for the purpose as described.

2. In a doublecylinder steam-engine with two coupled main-cranks, acting on two shafts, the combination with the main-cranks d a,

of an auxiliary guide-crank a coupled' to said I cranks a a, the cylinders being arrangedin an inclined position and the connecting-rods crossing each other, for the purpose as described.

3. In a double-cylinder, steam-engine with I two coupled'main-cran'ks acting ontwo shafts,

the combination with the maincranks a a, of an auxiliary guide-crank a coupled to said cranks a a, said crank a being adapted to act on thesteam-dist-ributer, the cylinders be ing arranged in an inclined position and the eccentric 70 adapted to act simultaneously on I the valves of both cylinders, for the purpose as described. I I

6. In a double-cylinder steam-engine with two coupled main cranks acting on two shafts, the combination with the main-cranks a a of an auxiliary guide-crank a coupled to said cranks a a, axle g of said crank a having eccentric 7i; adaptedto act simultaneously on the valves of both cylinders, the latter being arranged in an inclined position and the corn meeting-rods crossing each'other, for the purpose as described.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

HERMANN FRIEDEB'ORN.

Witnesses:

I LoUIs MiiLLER,

WILHELM SCHMIDT. 

